Improvement in looks foe drawees



. @eine tafrs ligature.

Letters Patent-No. 75,854, dated March 24, 1808.

IMPROVEMENT IN lLOGKS FOR DRAWERS, 6to.

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To ALL WuoM ir MAYeoNeEnN;

` Be it known that I, A, G. BURTON, of Rochester, in the 'county of Monroe, and State of New York, have invented certain ineiv and useful Improvements in Locks; vand I do hereby declare that the following is a full and exact description thereof, refer-'ence being had to the accompanying drawings, making part ot' this specication.

' Figure 1 is an edge elevation of my improved lock.

Figure 2, a front elevation.`

Figure 3, a central vertical section. Y

'Figure 4, a diagram,'showing the connection of the operating-bit or arm with the bolt.

Figure 5, a diagram, showing the arrangement and action of the tumblers.

Figure 6, a view -in' detail of the several operating parts detached.

Like letters of reference `indicate corresponding parts in all the figures.

The lock isY intended more especially for use on drawers, Ste.; and the object is to combine the parts of 'the lock in such a manner that it cannotbeeasily picked.

i As represented in the drawings, A is the lock-case, and B the bolt. The bolt is provided with a tail, a, by which it is guided, acircular shoulder, b, which rests against the end of the operating-arm or bit c, and a notch, d, for the said arm to strike into in rctracting or throwing the bolt. It..is also provided with a dog,f, for striking into the notches of the tumblers when set, as will presently be described. Thisforrn'ot' the bolt is most clearly exhibited in iig. 4.

The case is formed with abarrel, C, passing through the wood, for the insertion of the key. In this barrel rests a key-guide or bolt,D, of smaller diameter than the barrel, thereby leaving an open space, as clearly shown. The head e of this key-guide, covers the end ofthe barrel closely, and its lower end fits in or connects with the arm e, in any convenient manner, so as to give it motion. In the drawings it is shown as connecting by its end being'keyed in `an irregular-shaped eye, jf

The key-`guide D is provided with two wings, g z, at suitable positions, as shown in fig. 6. The wingg Y rests under 'a ange`or ledge, c', of. the barrel, so that when turned back, neither the key-guide nor the key that fits therein can be withdrawn. This arrangement is of advantage in post-oililce drawers, tills, &c., where it is desirable always tokeep them locked. If theI key cannot be removed except in one position, viz, when locked, it will insure the-closing of the drawer. .The wing h is intended for acting upon and disarranging the tumblers after they have been set by the key, as will presently be described. The key-guide is provided with a slit or groove, Ic, extend-ing down through on one side, 'inv which is insert-ed the key E. This key is provided 'with the ordinary bits ZZ l, which act upon thc tumblers. p

The tumblcrs Gr` G are preferably. made of the form indicated in fig. 5. They are pivoted at m, so as to turn out or in, and the ends which project forward have notches 'n for the dogf, of'the boit, to fall into when all are set. The tumblers also have cam-points, op, which are Vso situated in relation to the bits Z Z Z ofthe key, and the wing h of the key-guide,l that when turned in one direction, said bits of the key will strike the cam-points o, and throw the tumblers out to set thcuotches for the dog to fall into; and when turned back again,the said wing of the key-guide will strikethe cam-points p, to distribute the tumblers again. The notches at are irregularly situated in the respective tumblers, so that said tumblers will, some of thcmhbe thrown out to a greater extent than others, to make the notches coincide. The hits of the key are correspondingly made to project more or less to produce this effect. By this means the chances of picking the lock are greatly reduced, since the bits of the key must cach be fitted exactly to the extent of motion its tumblers must go through to set the notch. 4

Washers H H are fitted between the tumblcrs, for the double purpose of keeping them properly separated for thc action-of the key, and also to produce the nccessaryfriction on the tumblcrs tohold them-in any positionto which they are moved. It is a special design in my lock to avoid the use of springs, by employing friction to hold the tumblers in place. v

The operation will be readily understood. Suppose the arm c to bc at the extreme right, as in g. 5, the

first movement will bc to set the tumblers so that the dog can fall into the notches, which is accomplished by the bits of the key striking the cam-points o, as before described. During all this time that the tumblers are being set, the arm c holds against the shoulder b, of the bolt, so that no action can bring said bolt against the ends of the tumblers till the latter are in position to receive the dog. After the tumblers are set, the arm passes the shoulder and strikes into the notch d, to retract the bolt. This holding of the bolt out away from 'the ends of the tumbiers is of much importance, for it prevents them from jarring and losing their position, and prevents strain upon them, and also prevents picking easily, for the reason that no indication of the position of the tumblers can be attained without contact therewith. When the arm c retreats from its contact with the shoulder Za, to strike into the notch d, and retract the bolt, the key at that moment comes opposite or nearly opposite the pivot m. Therefore, if at that point the bolt comes in contact with the ends of the tumblers, no feeling can .be attained by the contact, for the reason that the key, or any picking-instrument, in its place, coming opposite the pivot, can have but little action in throwing the tumblers in either one direction or the other.

A Well-known loch is in use in which pins, pressed forward by springs, strike into the kcycyiinder, and prevent unlocking, and in which the bits of the key press said pins out, to allow the said cylinder to turn. My device diifers from -this inasmuch as I employ positive tumblcrs situated outside, instead oi' pins, which said tumblcrs are set in a fixed position to allow the bolt to retract.

What I claim as my invention, and desire to secure by Letters Patent, is

1, In combination with the key guide D and friction-tumblers G G, the counter-cams y t, the former operating to retain the key-guide and key as described,'and the latter to distribute the tumblcrs, substantially as set forth. l

2. The combination, with the key-guide D, of the shielding-barre1 C, of larger diameter, closed by thc head e, and so arranged as to leave ample space between the body of the guide and the barrel, for the operation of the Wings y t, or their equivalent, substantially as and for the purposes set forth.

3. So arranging they key E with relation to the arm c and shoulder Z1, that when the said arm relieves the said shoulder, to act upon the bolt, the key will come opposite, or nearly opposite, the pivot mwherc it can have the least action upon the tumbler-s, as herein set forth.

4. The Wing g, and the ledge when employed, in combination with the keyguide D and key E, to prevent its Withdrawal when the lock is unlocked, as herein set forth.

In Witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses,

A. G. BURTON.

Witnesses:

II. S. GREBNLEAF, R. F. OsGooD. 

